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Mechanical Engineering professor James Hone and Electrical Engineering Professor Kenneth Shepard teamed up for the research, the findings of which are published in Nature Nanotechnology. "This device is by far the smallest system that can create such FM signals," explained Hone.

Graphene, which is a single atomic layer of carbon, is the strongest material known to man and has electrical properties superior to silicon, making it a great material for tiny electromechanical systems at the nano-scale. It can be used to create scaled-down version of the microelectrocmechanical systems that are widely used in accelerometers and gyroscopes in smartphones, for example.

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This study harnessed graphene's stretching capabilities in order to tune the output frequency of a custom oscillator, thus creating a nano-scale version of a voltage controlled oscillator (VCO). VCOs turn a voltage input into a specific oscillation frequency and the team found it was possible to generate a frequency-modulated (FM) signal, which is used for FM radio broadcasts. The team built a graphene VCO (with a frequency of around 100 megahertz) by suspending a 2-4 micrometer-long strip of graphene above a metal electrode. By applying a voltage to the electrode, the graphene could be drawn down, the tension created altered the resonant frequence of the strop -- the stronger the pull towards the electrode, the higher the frequency. They then took songs from an iPhone -- they picked Gangnam Style in one example -- and fed it through to the graphene transmitter. The resulting signals were then picked up by a regular radio receiver.

Hone said: "This work is significant in that it demonstrates an application of graphene that cannot be achieved using conventional materials. And it's an important first step in advancing wireless signal processing and designing ultra-thin, efficient cell phones.

Our devices are much smaller than any other sources of radio signals, and can be put on the same chip that's used for data processing."

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These tiny transmitters could have applications in wireless signal processing for mobile phones, for example. It's unlikely they'd end up replacing conventional radio transmitters, where size isn't so important. Graphene transmitters could be both very compact and can be tuned over a wide range.